Using --delimiter / on Git Bash resolves to "C:/Program Files/Git" instead of "/", regardless of (single|double) quotes used #10769

Describe the bug

Consider the following command.

aws s3api list-objects-v2 --no-paginate --bucket SOME_BUCKET --prefix SOME_PREFIX --delimiter '/'

According to the AWS Documentation, you would expect this to return the Common Prefixes functionality.

If I run this command on Windows Command Prompt, I get a subsection in my JSON called "CommonPrefixes", exactly as expected.

But running the exact same command on Git Bash will have no "CommonPrefixes" section in my outputted JSON, and the delimiter will be listed as "Delimiter": "C:/Program Files/Git".

Now, maybe this is something that can be solved with better documentation. But, no matter how I tried -- with single quotes, double quotes, in a file, out of a file, etc., it would always create the delimiter as "C:/Program Files/Git/".

And for context, Git Bash is nothing more than a wrapper around Mintty -- a CLI tool that allows Windows users to get a minimal UNIX like shell running on Windows. And Git Bash comes as a part of the installation when you install Git on Windows. So, this is a problem for anyone using Git Bash (many people).

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

I expected to get a "CommonPrefixes" section in my outputted JSON, and for the delimiter to be the original "/" I provided it with.

Current Behavior

The "/" gets reinterpreted to mean the root of my shell, which is "C:/Program Files/Git/".

Reproduction Steps

1. Create a bucket called SOME_BUCKET.
2. Add the following files to it.
   • a/b1/c1
   • a/b1/c2
   • a/b2/c1
   • a/b2/c2
3. On a Windows machine with a standard Git Bash installation, run the following command.
4. aws s3api list-objects-v2 --no-paginate --bucket SOME_BUCKET --prefix abc/ --delimiter '/'

Possible Solution

This issue is technically caused by GitBash/Mintty. More context here -- https://stackoverflow.com/questions/58677021

Long story short, GitBash/Mintty tries to be helpful, and replaces all standalone instances of "/" with whatever root folder of Git Bash -- in my case, "C:/Program Files/Git/".

However, this behaviour can be opted out of -- by prepending the command with the following.

MSYS_NO_PATHCONV=1

So, I can change the command to be like this instead.

MSYS_NO_PATHCONV=1 aws s3api list-objects-v2 --no-paginate --bucket SOME_BUCKET --prefix SOME_PREFIX --delimiter '/'

And now, everything works perfectly.

So, I propose that AWS CLI adds a check to see if it is running on MSYS (the underlying system for Mintty/GitBash), and then add this prefix.

It will do no harm and is a very simple change, not to mention it saves an extremely difficult debugging session for the poor soul who has found GitBash/Mintty an otherwise pleasant experience when used with AWS CLI.

Additional Information/Context

This won't just solve the problem for GitBash, but anyone using Mintty. That is a lot of users, and a lot of headache avoided by a not-too-heavy lift from you all.

CLI version used

GitBash -- git version 2.56.0.windows.1

Environment details (OS name and version, etc.)

Microsoft Windows 11 Enterprise -- 10.0.22631 Build 22631